Electric-resistance device.



L. W. CHUBB ELECTRIC RESISANCE DEVICE.

APPLlCATiON HLSD 1^N|6,19l5.

Patented May 28,1918..

INVENTOR PW/'5 W Chubb.

WlTNESSES ATTORNEY gea cti

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a noinilin-orming metal provided with a coating of aluminum.. The cooling liquid may be Water or any other desired .cooling liquid, but l prefer to employ, as the cooling liquid, a solution of a film-forming electro-- lyte, in order that any breaks that may occur in the insulatinglilin upon the resistance elements, by reason oit' n'iechanical shocks or electrical rupture, may bepautomatically and immediately. repaired.

rlhe accompanying drawing illustrates the application of my invention to the cooling of the control. resistors in the secondary eircuit of a three-phase induction motor. The primary and secondary windings of the motor are indicated diagrammatically at l and 2, and phase conductors 3 connect the secondary Winding 2 with resistors 4, 5 and 6, which are electrically star-connected at the point 7. llhe resistance elements et, 5 and 6., are inclosed Within a tank 8 provided with an outlet opening 9 that is connected, by :means et a pipe l0, to a cooling,- coil ll contained Within a. tank l2 which should pret-- erably be disposed at a higher level than the top of the tank 8. The tank l2 is provided with inlet and outlet pipes l?, and lf3; by means ot which Water or other fluid can be circulated through the tank l2, and the cooling coil ll is connected, by means of a pipe l5, to an inlet opening 1 6 in the tank. 8. llhe tank S contains a body of liquid 17, "which may till the tanlr either partly, as shown, or completely. rlhis liquid. may be Water or any other desired cooling liquid, but, stated above, l prefer that it shall contain a 51m-forming electrolyte. llt the liquid l? tills the tanlr 8 only partly, as shown in the drawing, the heat generated in the resistors 4, 5 and G will vaporize the liquid, and the vapor will be conducted through the opening, 9 and the pipe l() to the cooling' coil il, which is kept cool by a circulation ot' Water or other coolingliuid through the tanli l2, and the liquid condonsed in the coil 1l will be returned through the pipe to the inlet openinglo oi the tank S, lf the amount of liquid l? is sutiicient to lill the tank 8 and the coil ll, the

t' heated liquid will itselil circulate througa the pipe 10, cooling coilll and return pipe l5. ln this case, a safety outlet should be provided for the coil ll in order to prevent Each of the resistancemembers 4t, 5 and 6 may be constructed in the manner shown in Fig. 2, which shows a core of film-orming conducting material supporting a series of strips 2l oi' wood or other non-conducting material upon which is non-inductively Wound a conductor Wire 22, preierably of aluminum. `One terminal ot the coil 22 is attached to the conducting body 20 at 23,' and the other vterminal i4 is adapted to be connected to the neutral point 7 of the starconnection. The conducting body 2() eX- tends through a suitable packing device 25 disposed in the Wall of the tank 8 and is provided with a suitable terminal 26 whichI is secured in place by means of nuts 27.

The arrangement shown in the drawing is Well adapted for use in connection With the large electric machines employed in naval service, in which case the tank l2 may be supplied with 'a constant current of sea Water. lt is to be noted that, While the energy developed in the resistance members is dissi* pated by means ot sea water, the Water itself does not come into contact with such members. Leakage currents ar dangerous stresses between the resistance elements and the highly comlucting:r sca water are thereby avoided.

rlhc system described above is particularly well adapted i'or use in cooling resistance elements that are inserted in direct-current circuits and for cooling the control resistors oi induction motors where the frequency is low and where electrolysis is a source of serious trouble when the resistors are cooled 'with electrically conducting liquids.

My invention is capable of numerous other applications in addition to those just described. lFor example, testing rheostats embodying my invention may be substituted lor the present equipments which now include water rheostats and air cooled racks. A sa ving in cost, space and weight may thus be ed'cctcd and the dirt, corrosion and electrical oscillations oi thc Water rheostat be avoided. My invention also linde applica tion in electric steam boilers for heating purposes and for the generation of steam ior heating or for motive power. All such modifications and adaptations are comprehended within the scope of my invention, which is therefore to be limited only by the scope of the appended claims.

l claim as my invention:

l. An electric resistance elementl provided with a covering which acts as an electrical insulator but has substantially no heat-insulating effect. I

2. in electric resistance device comprisingr a re tance clement provided ivith a covering which acts as an electrical insulator but has substantially no heat-insulating effect, and means for surrounding the said resistance element with a cooling liuid. i

ing a body oi aluminum provided with an' c'lectrolytic insulating film.

5. An electric resistance device comprising a resistance element having a surface covered with an clectrolytic insulating film, and means for surrounding the said resistance element with a cooling fluid.

6. An electric resistance device comprising a resistance Aelement covered with an electrolytic insulating lihn, means tor surrounding the said resistance clement with a cooling fluid, and means for` removing heat from the said fluid.

7. An electric resistance device comprising a resistance element having a surface covered with an clectrolyl'ic insulating ilm, and means for surrounding the said resistance element with cooling liquid containing a film-forming electrolyte.

8. An electric resistance device comprising a resistance element having a surface covered with an electrolytic insulating film, means for surrounding the said resistance element with a cooling liquid containing a film-forming electrolyte, and means for re movingheat from the said liquid.

9. An electric resistance device comprising a resistance element having a surface covered with an electrolytie insulating film, a casing for inclosing the said element, and means for causing cooling Huid to circulate through the said casing.

10. An electric,resistance Vdevice comprising a resistance element having a surface covered with an electrolytic insulating film, a casing for inclosing the said element, and means for causing a cooling liquid containing a film-forming electrolyte to circulate through the said casing.

11. An electric resistance device comprising an aluminum resistance element covered with an electrolytlc msulatmg film and having a surface4 means for surrounding the said resistance.

element with a cooling fluid.

12. An electric resistance device comprising an aluminum with an electrolytic insulating .lilm and resistance element coveredmeans for surrounding the said element withy a cooling liquid electrolyte.

13. An electric resistance device comprising a resistance element having a surface covered with an electrolytic insulating hlm, a liquid-containing casing for inclosing the said element, a second casing containing a cooling coil, means for effecting communlcation between the said cooling coil and the said first-named casing and means for causing cooling nuid to circulate through 'the said second casing. e

14e. An electric resistance element comprising a core oi'conducting material, a coil of resi/stance material surrounding the said core and provided with an electrolytio'finsulzying film, and spacing strips of norcofiducting material interposed between the prevent current from leaving containing a film-forming' subscribed my name this 31st day of Dec; V

LEWIS W. CHUBB. Witnesses.:

O. W. A. O'rrLING, B. B. Hmm. 

